1. The Field of the Invention
The present invention relates to a detachable support arm having a toolless attachment portion. In particular, although not exclusively, the invention relates to a detachable support arm having a toolless attachment portion which is attachable to an arm assembly of a chair to support a tablet work surface. However, the support arm may be used to support a number of different items. Further, the support arm also has application beyond chairs.
2. The Relevant Technology
In order to provide a work surface which does not take up excessive space, it is known to attach the work surface to a chair, such as a chair in a university lecture theatre for example, rather than providing a separate table or desk. Such work surfaces are often permanently affixed to the chairs. It is known to provide a detachable tablet or work surface for attachment to a chair, although known detachable tablets generally require fastening to part of the chair through bolts or screws. Attachment or detachment may require the use of a tool and can be time consuming.
In the modern office environment it may be useful for a chair occupant to be able to readily attach and detach a work surface to his office chair, in a short amount of time and with minimum fuss. Most office workers do not have readily-available tools in order to attach such a work surface to their chair.
It is therefore an object of the present invention to provide a support arm which is more readily attachable and detachable and/or which at least provides the public with a useful choice.
In accordance with a first aspect of the present invention, there is provided a support arm for supporting an item from a tapered member such as a tapered chair arm, the support arm including: an arm portion having a proximal end and a distal end; at or toward the distal end, an arrangement for mounting an item; and at or toward the proximal end, an attachment portion defining an internal taper, whereby the support arm is engageable on the tapered member in a taper lock between the tapered member and the attachment portion and disengageable manually and without the use of tools, to mount the support arm to the tapered member.
The internal taper of the attachment portion preferably substantially corresponds to the taper of the tapered member.
Preferably, the tapered member converges towards its upper end, and the internal taper in the attachment portion of the support arm converges towards its upper end, so that moving the attachment portion downwardly relative to the tapered member engages the respective tapers together. It will be appreciated that such a movement could be achieved under the influence of, or assisted by, gravity.
Suitably, the tapered member has an eccentric or polygonal shape in cross section, with the interior of the attachment portion having a cross-sectional shape which substantially corresponds to at least part of the shape of the tapered member so that rotation between the attachment portion and tapered member is inhibited when the tapers are engaged. The tapered member is preferably substantially square or rectangular in cross section.
Preferably, the attachment portion has an open part so that the interior of the attachment portion may be engaged with the tapered member by moving it into contact from the side, front or rear of the tapered member, and then sliding the attachment portion along the tapered member so that the tapers engage. More preferably, the attachment portion has an open side so that the interior of the attachment portion may be engaged with the tapered member by moving it into contact from the side of the tapered member, and then sliding the attachment portion along the tapered member so that the tapers engage. This is particularly suitable when the support arm is to be mounted to a chair arm, as it enables the attachment portion to be engaged with the chair arm by moving it in a sideways manner from the side of the chair opposite to the seating surface. It will be appreciated that the attachment portion may be arranged to be moved towards the chair arm from the left side or right side of the chair, depending on particular requirements.
The attachment portion is preferably substantially “C” shaped in internal cross section. The attachment portion preferably includes protrusions extending from the edges of the substantially “C” shape, partially across the open part, the protrusions sized to make it more difficult for the attachment portion to be removed in a sideways manner from the tapered member when the tapered parts are engaged, but to allow the attachment portion to be removed through the spaces between the protrusions when the tapered parts are not engaged.
In a preferred embodiment, the interior of the attachment portion includes one or more release shuttles, each of which is slidable relative to the attachment portion and arranged to engage the outer surface of the tapered member when the tapered member and the attachment portion are engaged. Advantageously, the attachment portion is substantially “C” shaped in internal cross section, and the or each spring-loaded release shuttle is substantially “C” shaped. The ends of the substantial “C” shape of the or each shuttle preferably extends so as to make it more difficult for the attachment portion to be removed in a sideways manner from the tapered member when the tapered parts are engaged, but to allow the attachment portion to be removed through the spaces between the ends of the shuttle(s) when the tapered portions are not engaged. When the attachment portion includes protrusions extending from the edges of the substantially “C” shape, the or each release shuttle is preferably substantially aligned with respective protrusions extending from the substantially “C” shaped attachment portion.
Suitably, the included angle between the front and rear inner surfaces of the or each release shuttle substantially corresponds to the included angle between the front and rear outer surfaces of the tapered member. The included angle between the front and rear inner surfaces of the or each release shuttle is preferably about 2 to 3 degrees.
Preferably, the included angle between the front and rear outer surfaces of the or each release shuttle, and the included angle between the front and rear inner surfaces of the attachment portion in the region of the or each release shuttle, is greater than the included angle between the front and rear inner surfaces of the or each release shuttle. The included angle between the front and rear outer surfaces of the or each release shuttle, and the included angle between the front and rear inner surfaces of the attachment portion in the region of the or each release shuttle, is preferably about 14 degrees.
Preferably, the included angle between the side inner surfaces of the or each release shuttle substantially corresponds to the included angle between the side outer surfaces of the tapered member. The included angle between the side inner surfaces of the or each release shuttle is preferably about 2 to 3 degrees.
Advantageously, the included angle between the side outer surfaces of the or each release shuttle, and the included angle between the side inner surfaces of the attachment portion in the region of the or each release shuttle, is greater than the included angle between the side inner surfaces of the or each release shuttle. The included angle between the side outer surfaces of the or each release shuttle, and the included angle between the side inner surfaces of the attachment portion in the region of the or each release shuttle, is preferably about 14 degrees.
In a most preferred embodiment, all inner and outer surfaces of the or each release shuttle, and of the attachment portion in the region of the or each release shuttle, are tapered. Preferably, the included angles between all opposing outer surfaces of the or each release shuttle, and between all opposing inner surfaces of the attachment portion in the region of the or each release shuttle, are greater than the included angles between all opposing inner surfaces of the or each release shuttle. The included angles between all opposing internal surfaces of the or each release shuttle are preferably about 2 to 3 degrees. The included angles between all opposing outer surfaces of the or each release shuttle, and between all opposing inner surfaces of the attachment portion in the region of the or each release shuttle, are preferably about 14 degrees.
In a preferred embodiment, at least a substantial part of the remainder of the interior of the attachment portion, other than the region(s) corresponding to the release shuttle(s), has an angle substantially corresponding to that of the tapered member.
Preferably, the or each release shuttle is biased towards the tapered end of the attachment portion. The or each release shuttle is preferably biased by one or more compression springs. Alternatively, the or each release shuttle may be biased by one or more leaf springs. Advantageously, the or each biased release shuttle is arranged such that as the attachment portion of the support arm is moved in the direction of its taper to detach it from the tapered member, the or each release shuttle initially moves with the tapered member, relative to the attachment portion, in a direction away from the taper and then snaps out of engagement with the tapered member to release the attachment portion from the tapered member.
Preferably, the or each release shuttle has a respective stop provided in the interior of the attachment portion to limit the movement of the or each release shuttle in a direction away from the taper.
The or each release shuttle is suitably made of a plastics material, and may be made from a self-lubricating plastic such as nylon for example.
It is preferred that two spaced release shuttles are provided in the attachment portion.
The arrangement for mounting an item preferably comprises a joint to which the item is attachable or attached. The item may be permanently mounted to the joint. Alternatively, the item may be removable from the joint and interchangeable with a further item. A “quick release” mechanism may be provided for that purpose.
The position of the item may be fixed relative to the arm assembly when the item is attached to the joint.
Alternatively, the joint may be configured to allow pivoting and rotating movement of the item relative to the arm portion. A pivoting and rotating joint is particularly useful when the support arm is to be attached to the arm of an office chair, as it enables the user to easily egress the chair, which is important for safety purposes. The pivoting and rotating joint is preferably indexed for rotation. In a preferred embodiment, the joint is indexed for rotation such that an item attached to the joint may be rotated up to about 20 degrees towards the user and up to about 30 degrees away from the user in a substantially horizontal plane.
The joint allows movement of the item between a use position in which it extends in a substantially perpendicular manner from the arm portion (for example over a seating surface of a chair when the support arm is mounted to a chair arm) and a storage portion in which it hangs beside the arm portion. The joint is preferably configured such that with the support arm attached to an arm of a chair and an item attached to the joint, a chair occupant can pivot the item in a substantially vertical plane towards the side of the chair so that it falls under the influence of gravity to the outside of the arm portion, or can rotate the item towards the front of the chair a sufficient distance that it will then pivot under the influence of gravity to the outside of the arm portion.
The arrangement to attach an item, or the item itself, may be configured to allow sliding of the item in at least one dimension relative to the arm portion. Preferably, the item is slidable in two dimensions relative to the arm portion.
The arm portion is preferably curved upwardly from the attachment portion such that the item is located above and forward of the attachment portion when the support arm is attached to a tapered member.
The arm portion may include a projection at or towards the distal end thereof, thereby forming a dogleg configuration, with the arrangement to attach an item provided at or adjacent a distal end of the projection.
The item is preferably one or more selected from the group of: a work surface or tablet, a work box for containing writing implements, a keyboard, a mouse pad, a notebook computer, and a cup holder. The item is most preferably a work surface mounted at or adjacent the distal end of the arm portion. The work surface is most preferably in the form of a tablet.
The tablet advantageously includes a cup holder to hold a cup, glass, tumbler, or the like.
The cup holder may be arranged to move between a position located in a recess in the tablet and a position located adjacent the tablet. The cup holder may be pivotally connected to the tablet. Alternatively, the cup holder may be slidably mounted in the tablet. The cup holder may include a four bar linkage to provide a cup supporting base when the cup holder is positioned adjacent the tablet, and which folds up upon returning the cup holder to the recess.
The cup holder preferably includes an elastomeric section to stabilize an item therein.
In accordance with a second aspect of the present invention, there is provided a support arm for supporting a work surface from a tapered chair arm, the support arm including: an arm portion having a proximal end and a distal end; a work surface mounted at or toward the distal end; and at or toward the proximal end, an attachment portion defining an internal taper, whereby the support arm is engageable on the tapered member in a taper lock between the tapered member and the attachment portion and disengageable manually and without the use of tools, to mount the support arm to the tapered member.
The tapered member may converge towards its upper end, and the internal taper in the attachment portion of the support arm may converge towards its upper end, so that moving the attachment portion downwardly relative to the tapered member engages the respective tapers together.
The work surface may be moveable between a position in which it extends in a substantially perpendicular manner from the arm portion and a storage portion in which it hangs beside the arm portion.
The work surface is preferably in the form of a tablet.
Preferably, the tablet includes a cup holder to hold a cup, glass, tumbler, or the like, and the cup holder is arranged to move between a position located in a recess in the tablet and a position located adjacent the tablet.
In accordance with a third aspect of the present invention, there is provided a chair comprising a base supporting a seat, a back, and a pair of tapered arm members, with a support arm as outlined in respect of either the first or second aspect above attached to one of the arm members, the support arm being disengageable from the arm member by moving it upwardly and outwardly relative to the arm member.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
The invention consists in the foregoing and also envisages constructions of which the following gives examples only.